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Title

Configurationally Stable Doubly Bridged Biphenyl Azocines through Copper-Catalyzed Double Carbene Insertions into the Corresponding Azepines
Authors
Harthong, Steven
Brun, Elodie
Grass, Stéphane
Besnard, Céline
Buergi, Thomas
Lacour, Jérôme
Published in Synthesis. 2016, vol. 48, no. 19, p. 3254-3262
Abstract Doubly bridged biphenyl azocines can be prepared in a single step through copper-catalyzed reactions of a doubly bridged biphenyl azepine and diazodiester reagents. Double [1,2]-Stevens rearrangements occur at 100 °C to afford doubly tethered eight-membered rings (49 to 61%) as trans and cis regioisomers (1:1 ratio). These products present an axial chirality. ECD and VCD analyses of the separated enantiomers (CSP-HPLC) were used to assign the absolute configuration. High configurational stability is observed for both regioisomers as racemization does not occur after 1 week of heating at 208 °C in dodecane (ΔG ‡ > 41 kcal·mol–1). Interestingly, reactions performed at 40 °C retain a certain level of enantiospecificity (82–86%), avoiding, for the most part, thermal racemization of the starting material.
Keywords Azepine — Azocine — Carbenes — Configurational stability — [1,2]-Stevens rearrangement — Ylides
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Article (Published version) (975 Kb) - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://www.thieme-connect.de/DOI/DOI?10.1055/s-0035-1562467
Structures
Faculté des sciences / Section de chimie et biochimie / Département de chimie physique
Faculté des sciences / Section de chimie et biochimie / Département de chimie organique
Research groups Groupe Lacour
Groupe Bürgi
Citation
(ISO format) 		HARTHONG, Steven et al. Configurationally Stable Doubly Bridged Biphenyl Azocines through Copper-Catalyzed Double Carbene Insertions into the Corresponding Azepines. In: Synthesis, 2016, vol. 48, n° 19, p. 3254-3262. https://archive-ouverte.unige.ch/unige:86678

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Deposited on : 2016-09-05

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